Specifications: 22 ventilation channels has optimal strength, weight and ventilation. Shock-absorbing EPS (expanded polystyrene) foam is molded directly onto the outer hard shell. With the adjustment dial with precision interlock, it is easy to adjust and adapt to personal comfort. The front vent covered by the grid prevents bugs and debris from entering the interior. Meanwhile, the adjustable helmet means that the goggles can be easily accommodated. Item Name: Riding Helmet Material: PC, EPS Features: Durable, Breathable, Comfortable M/L Size: Suitable for Head Girth: 55cm-61cm/21.65"-24.02" (Approx.) Notes: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 x Riding Helmet